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<a name="gstreamer-libs-GstTypeFindHelper"></a><div class="titlepage"></div>
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<h2><span class="refentrytitle"><a name="gstreamer-libs-GstTypeFindHelper.top_of_page"></a>GstTypeFindHelper</span></h2>
<p>GstTypeFindHelper — Utility functions for typefinding</p>
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<td class="gallery_image" valign="top" align="right"></td>
</tr></table></div>
<div class="refsect1">
<a name="gstreamer-libs-GstTypeFindHelper.functions"></a><h2>Functions</h2>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="functions_return">
<col class="functions_name">
</colgroup>
<tbody>
<tr>
<td class="function_type">
<a href="../html/GstCaps.html#GstCaps-struct"><span class="returnvalue">GstCaps</span></a> *
</td>
<td class="function_name">
<a class="link" href="gstreamer-libs-GstTypeFindHelper.html#gst-type-find-helper" title="gst_type_find_helper ()">gst_type_find_helper</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a href="../html/GstCaps.html#GstCaps-struct"><span class="returnvalue">GstCaps</span></a> *
</td>
<td class="function_name">
<a class="link" href="gstreamer-libs-GstTypeFindHelper.html#gst-type-find-helper-for-buffer" title="gst_type_find_helper_for_buffer ()">gst_type_find_helper_for_buffer</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a href="../html/GstCaps.html#GstCaps-struct"><span class="returnvalue">GstCaps</span></a> *
</td>
<td class="function_name">
<a class="link" href="gstreamer-libs-GstTypeFindHelper.html#gst-type-find-helper-for-buffer-with-extension" title="gst_type_find_helper_for_buffer_with_extension ()">gst_type_find_helper_for_buffer_with_extension</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a href="../html/GstCaps.html#GstCaps-struct"><span class="returnvalue">GstCaps</span></a> *
</td>
<td class="function_name">
<a class="link" href="gstreamer-libs-GstTypeFindHelper.html#gst-type-find-helper-for-extension" title="gst_type_find_helper_for_extension ()">gst_type_find_helper_for_extension</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a href="../html/GstCaps.html#GstCaps-struct"><span class="returnvalue">GstCaps</span></a> *
</td>
<td class="function_name">
<a class="link" href="gstreamer-libs-GstTypeFindHelper.html#gst-type-find-helper-for-data" title="gst_type_find_helper_for_data ()">gst_type_find_helper_for_data</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a href="../html/GstCaps.html#GstCaps-struct"><span class="returnvalue">GstCaps</span></a> *
</td>
<td class="function_name">
<a class="link" href="gstreamer-libs-GstTypeFindHelper.html#gst-type-find-helper-for-data-with-extension" title="gst_type_find_helper_for_data_with_extension ()">gst_type_find_helper_for_data_with_extension</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a href="../html/GstPad.html#GstFlowReturn"><span class="returnvalue">GstFlowReturn</span></a>
</td>
<td class="function_name">
<span class="c_punctuation">(</span><a class="link" href="gstreamer-libs-GstTypeFindHelper.html#GstTypeFindHelperGetRangeFunction" title="GstTypeFindHelperGetRangeFunction ()">*GstTypeFindHelperGetRangeFunction</a><span class="c_punctuation">)</span> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a href="../html/GstCaps.html#GstCaps-struct"><span class="returnvalue">GstCaps</span></a> *
</td>
<td class="function_name">
<a class="link" href="gstreamer-libs-GstTypeFindHelper.html#gst-type-find-helper-get-range" title="gst_type_find_helper_get_range ()">gst_type_find_helper_get_range</a> <span class="c_punctuation">()</span>
</td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect1">
<a name="gstreamer-libs-GstTypeFindHelper.includes"></a><h2>Includes</h2>
<pre class="synopsis">#include &lt;gst/base/base.h&gt;
</pre>
</div>
<div class="refsect1">
<a name="gstreamer-libs-GstTypeFindHelper.description"></a><h2>Description</h2>
<p>Utility functions for elements doing typefinding:
<a class="link" href="gstreamer-libs-GstTypeFindHelper.html#gst-type-find-helper" title="gst_type_find_helper ()"><code class="function">gst_type_find_helper()</code></a> does typefinding in pull mode, while
<a class="link" href="gstreamer-libs-GstTypeFindHelper.html#gst-type-find-helper-for-buffer" title="gst_type_find_helper_for_buffer ()"><code class="function">gst_type_find_helper_for_buffer()</code></a> is useful for elements needing to do
typefinding in push mode from a chain function.</p>
</div>
<div class="refsect1">
<a name="gstreamer-libs-GstTypeFindHelper.functions_details"></a><h2>Functions</h2>
<div class="refsect2">
<a name="gst-type-find-helper"></a><h3>gst_type_find_helper ()</h3>
<pre class="programlisting"><a href="../html/GstCaps.html#GstCaps-struct"><span class="returnvalue">GstCaps</span></a> *
gst_type_find_helper (<em class="parameter"><code><a href="../html/GstPad.html#GstPad-struct"><span class="type">GstPad</span></a> *src</code></em>,
                      <em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guint64"><span class="type">guint64</span></a> size</code></em>);</pre>
<p>Tries to find what type of data is flowing from the given source <a href="../html/GstPad.html#GstPad-struct"><span class="type">GstPad</span></a>.</p>
<p>Free-function: gst_caps_unref</p>
<div class="refsect3">
<a name="gst-type-find-helper.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>src</p></td>
<td class="parameter_description"><p>A source <a href="../html/GstPad.html#GstPad-struct"><span class="type">GstPad</span></a></p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>size</p></td>
<td class="parameter_description"><p>The length in bytes</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gst-type-find-helper.returns"></a><h4>Returns</h4>
<p>the <a href="../html/GstCaps.html#GstCaps-struct"><span class="type">GstCaps</span></a> corresponding to the data
stream.  Returns <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if no <a href="../html/GstCaps.html#GstCaps-struct"><span class="type">GstCaps</span></a> matches the data stream. </p>
<p><span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>][<acronym title="NULL may be passed as the value in, out, in-out; or as a return value."><span class="acronym">nullable</span></acronym>]</span></p>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-type-find-helper-for-buffer"></a><h3>gst_type_find_helper_for_buffer ()</h3>
<pre class="programlisting"><a href="../html/GstCaps.html#GstCaps-struct"><span class="returnvalue">GstCaps</span></a> *
gst_type_find_helper_for_buffer (<em class="parameter"><code><a href="../html/GstObject.html#GstObject-struct"><span class="type">GstObject</span></a> *obj</code></em>,
                                 <em class="parameter"><code><a href="../html/GstBuffer.html#GstBuffer-struct"><span class="type">GstBuffer</span></a> *buf</code></em>,
                                 <em class="parameter"><code><a href="../html/gstreamer-GstTypeFind.html#GstTypeFindProbability"><span class="type">GstTypeFindProbability</span></a> *prob</code></em>);</pre>
<p>Tries to find what type of data is contained in the given <a href="../html/GstBuffer.html#GstBuffer-struct"><span class="type">GstBuffer</span></a>, the
assumption being that the buffer represents the beginning of the stream or
file.</p>
<p>All available typefinders will be called on the data in order of rank. If
a typefinding function returns a probability of <a href="../html/gstreamer-GstTypeFind.html#GST-TYPE-FIND-MAXIMUM:CAPS"><code class="literal">GST_TYPE_FIND_MAXIMUM</code></a>,
typefinding is stopped immediately and the found caps will be returned
right away. Otherwise, all available typefind functions will the tried,
and the caps with the highest probability will be returned, or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if
the content of the buffer could not be identified.</p>
<p>Free-function: gst_caps_unref</p>
<div class="refsect3">
<a name="gst-type-find-helper-for-buffer.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>obj</p></td>
<td class="parameter_description"><p>object doing the typefinding, or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> (used for logging). </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="NULL is OK, both for passing and for returning."><span class="acronym">allow-none</span></acronym>]</span></td>
</tr>
<tr>
<td class="parameter_name"><p>buf</p></td>
<td class="parameter_description"><p>a <a href="../html/GstBuffer.html#GstBuffer-struct"><span class="type">GstBuffer</span></a> with data to typefind. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Parameter for input. Default is transfer none."><span class="acronym">in</span></acronym>][<acronym title="Don't free data after the code is done."><span class="acronym">transfer none</span></acronym>]</span></td>
</tr>
<tr>
<td class="parameter_name"><p>prob</p></td>
<td class="parameter_description"><p>location to store the probability of the found
caps, or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a>. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Parameter for returning results. Default is transfer full."><span class="acronym">out</span></acronym>][<acronym title="NULL is OK, both for passing and for returning."><span class="acronym">allow-none</span></acronym>]</span></td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gst-type-find-helper-for-buffer.returns"></a><h4>Returns</h4>
<p>the <a href="../html/GstCaps.html#GstCaps-struct"><span class="type">GstCaps</span></a> corresponding to the data,
or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if no type could be found. The caller should free the caps
returned with <a href="../html/GstCaps.html#gst-caps-unref"><code class="function">gst_caps_unref()</code></a>. </p>
<p><span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>][<acronym title="NULL may be passed as the value in, out, in-out; or as a return value."><span class="acronym">nullable</span></acronym>]</span></p>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-type-find-helper-for-buffer-with-extension"></a><h3>gst_type_find_helper_for_buffer_with_extension ()</h3>
<pre class="programlisting"><a href="../html/GstCaps.html#GstCaps-struct"><span class="returnvalue">GstCaps</span></a> *
gst_type_find_helper_for_buffer_with_extension
                               (<em class="parameter"><code><a href="../html/GstObject.html#GstObject-struct"><span class="type">GstObject</span></a> *obj</code></em>,
                                <em class="parameter"><code><a href="../html/GstBuffer.html#GstBuffer-struct"><span class="type">GstBuffer</span></a> *buf</code></em>,
                                <em class="parameter"><code>const <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gchar"><span class="type">gchar</span></a> *extension</code></em>,
                                <em class="parameter"><code><a href="../html/gstreamer-GstTypeFind.html#GstTypeFindProbability"><span class="type">GstTypeFindProbability</span></a> *prob</code></em>);</pre>
<p>Tries to find what type of data is contained in the given <a href="../html/GstBuffer.html#GstBuffer-struct"><span class="type">GstBuffer</span></a>, the
assumption being that the buffer represents the beginning of the stream or
file.</p>
<p>All available typefinders will be called on the data in order of rank. If
a typefinding function returns a probability of <a href="../html/gstreamer-GstTypeFind.html#GST-TYPE-FIND-MAXIMUM:CAPS"><code class="literal">GST_TYPE_FIND_MAXIMUM</code></a>,
typefinding is stopped immediately and the found caps will be returned
right away. Otherwise, all available typefind functions will the tried,
and the caps with the highest probability will be returned, or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if
the content of the buffer could not be identified.</p>
<p>When <em class="parameter"><code>extension</code></em>
 is not <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a>, this function will first try the typefind
functions for the given extension, which might speed up the typefinding
in many cases.</p>
<p>Free-function: gst_caps_unref</p>
<div class="refsect3">
<a name="gst-type-find-helper-for-buffer-with-extension.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>obj</p></td>
<td class="parameter_description"><p>object doing the typefinding, or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> (used for logging). </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="NULL is OK, both for passing and for returning."><span class="acronym">allow-none</span></acronym>]</span></td>
</tr>
<tr>
<td class="parameter_name"><p>buf</p></td>
<td class="parameter_description"><p>a <a href="../html/GstBuffer.html#GstBuffer-struct"><span class="type">GstBuffer</span></a> with data to typefind. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Parameter for input. Default is transfer none."><span class="acronym">in</span></acronym>][<acronym title="Don't free data after the code is done."><span class="acronym">transfer none</span></acronym>]</span></td>
</tr>
<tr>
<td class="parameter_name"><p>extension</p></td>
<td class="parameter_description"><p>extension of the media, or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a>. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="NULL is OK, both for passing and for returning."><span class="acronym">allow-none</span></acronym>]</span></td>
</tr>
<tr>
<td class="parameter_name"><p>prob</p></td>
<td class="parameter_description"><p>location to store the probability of the found
caps, or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a>. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Parameter for returning results. Default is transfer full."><span class="acronym">out</span></acronym>][<acronym title="NULL is OK, both for passing and for returning."><span class="acronym">allow-none</span></acronym>]</span></td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gst-type-find-helper-for-buffer-with-extension.returns"></a><h4>Returns</h4>
<p>the <a href="../html/GstCaps.html#GstCaps-struct"><span class="type">GstCaps</span></a> corresponding to the data,
or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if no type could be found. The caller should free the caps
returned with <a href="../html/GstCaps.html#gst-caps-unref"><code class="function">gst_caps_unref()</code></a>. </p>
<p><span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>][<acronym title="NULL may be passed as the value in, out, in-out; or as a return value."><span class="acronym">nullable</span></acronym>]</span></p>
</div>
<p class="since">Since: 1.16</p>
</div>
<hr>
<div class="refsect2">
<a name="gst-type-find-helper-for-extension"></a><h3>gst_type_find_helper_for_extension ()</h3>
<pre class="programlisting"><a href="../html/GstCaps.html#GstCaps-struct"><span class="returnvalue">GstCaps</span></a> *
gst_type_find_helper_for_extension (<em class="parameter"><code><a href="../html/GstObject.html#GstObject-struct"><span class="type">GstObject</span></a> *obj</code></em>,
                                    <em class="parameter"><code>const <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gchar"><span class="type">gchar</span></a> *extension</code></em>);</pre>
<p>Tries to find the best <a href="../html/GstCaps.html#GstCaps-struct"><span class="type">GstCaps</span></a> associated with <em class="parameter"><code>extension</code></em>
.</p>
<p>All available typefinders will be checked against the extension in order
of rank. The caps of the first typefinder that can handle <em class="parameter"><code>extension</code></em>
 will be
returned.</p>
<p>Free-function: gst_caps_unref</p>
<div class="refsect3">
<a name="gst-type-find-helper-for-extension.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>obj</p></td>
<td class="parameter_description"><p>object doing the typefinding, or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> (used for logging). </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="NULL is OK, both for passing and for returning."><span class="acronym">allow-none</span></acronym>]</span></td>
</tr>
<tr>
<td class="parameter_name"><p>extension</p></td>
<td class="parameter_description"><p>an extension</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gst-type-find-helper-for-extension.returns"></a><h4>Returns</h4>
<p>the <a href="../html/GstCaps.html#GstCaps-struct"><span class="type">GstCaps</span></a> corresponding to
<em class="parameter"><code>extension</code></em>
, or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if no type could be found. The caller should free
the caps returned with <a href="../html/GstCaps.html#gst-caps-unref"><code class="function">gst_caps_unref()</code></a>. </p>
<p><span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>][<acronym title="NULL may be passed as the value in, out, in-out; or as a return value."><span class="acronym">nullable</span></acronym>]</span></p>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-type-find-helper-for-data"></a><h3>gst_type_find_helper_for_data ()</h3>
<pre class="programlisting"><a href="../html/GstCaps.html#GstCaps-struct"><span class="returnvalue">GstCaps</span></a> *
gst_type_find_helper_for_data (<em class="parameter"><code><a href="../html/GstObject.html#GstObject-struct"><span class="type">GstObject</span></a> *obj</code></em>,
                               <em class="parameter"><code>const <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guint8"><span class="type">guint8</span></a> *data</code></em>,
                               <em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gsize"><span class="type">gsize</span></a> size</code></em>,
                               <em class="parameter"><code><a href="../html/gstreamer-GstTypeFind.html#GstTypeFindProbability"><span class="type">GstTypeFindProbability</span></a> *prob</code></em>);</pre>
<p>Tries to find what type of data is contained in the given <em class="parameter"><code>data</code></em>
, the
assumption being that the data represents the beginning of the stream or
file.</p>
<p>All available typefinders will be called on the data in order of rank. If
a typefinding function returns a probability of <a href="../html/gstreamer-GstTypeFind.html#GST-TYPE-FIND-MAXIMUM:CAPS"><code class="literal">GST_TYPE_FIND_MAXIMUM</code></a>,
typefinding is stopped immediately and the found caps will be returned
right away. Otherwise, all available typefind functions will the tried,
and the caps with the highest probability will be returned, or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if
the content of <em class="parameter"><code>data</code></em>
 could not be identified.</p>
<p>Free-function: gst_caps_unref</p>
<div class="refsect3">
<a name="gst-type-find-helper-for-data.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>obj</p></td>
<td class="parameter_description"><p>object doing the typefinding, or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> (used for logging). </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="NULL is OK, both for passing and for returning."><span class="acronym">allow-none</span></acronym>]</span></td>
</tr>
<tr>
<td class="parameter_name"><p>data</p></td>
<td class="parameter_description"><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>a pointer with data to typefind. </p></li></ul></div></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Don't free data after the code is done."><span class="acronym">transfer none</span></acronym>][<acronym title="Parameter points to an array of items."><span class="acronym">array</span></acronym> length=size]</span></td>
</tr>
<tr>
<td class="parameter_name"><p>size</p></td>
<td class="parameter_description"><p>the size of <em class="parameter"><code>data</code></em>
</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>prob</p></td>
<td class="parameter_description"><p>location to store the probability of the found
caps, or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a>. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Parameter for returning results. Default is transfer full."><span class="acronym">out</span></acronym>][<acronym title="NULL is OK, both for passing and for returning."><span class="acronym">allow-none</span></acronym>]</span></td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gst-type-find-helper-for-data.returns"></a><h4>Returns</h4>
<p>the <a href="../html/GstCaps.html#GstCaps-struct"><span class="type">GstCaps</span></a> corresponding to the data,
or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if no type could be found. The caller should free the caps
returned with <a href="../html/GstCaps.html#gst-caps-unref"><code class="function">gst_caps_unref()</code></a>. </p>
<p><span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>][<acronym title="NULL may be passed as the value in, out, in-out; or as a return value."><span class="acronym">nullable</span></acronym>]</span></p>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-type-find-helper-for-data-with-extension"></a><h3>gst_type_find_helper_for_data_with_extension ()</h3>
<pre class="programlisting"><a href="../html/GstCaps.html#GstCaps-struct"><span class="returnvalue">GstCaps</span></a> *
gst_type_find_helper_for_data_with_extension
                               (<em class="parameter"><code><a href="../html/GstObject.html#GstObject-struct"><span class="type">GstObject</span></a> *obj</code></em>,
                                <em class="parameter"><code>const <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guint8"><span class="type">guint8</span></a> *data</code></em>,
                                <em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gsize"><span class="type">gsize</span></a> size</code></em>,
                                <em class="parameter"><code>const <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gchar"><span class="type">gchar</span></a> *extension</code></em>,
                                <em class="parameter"><code><a href="../html/gstreamer-GstTypeFind.html#GstTypeFindProbability"><span class="type">GstTypeFindProbability</span></a> *prob</code></em>);</pre>
<p>Tries to find what type of data is contained in the given <em class="parameter"><code>data</code></em>
, the
assumption being that the data represents the beginning of the stream or
file.</p>
<p>All available typefinders will be called on the data in order of rank. If
a typefinding function returns a probability of <a href="../html/gstreamer-GstTypeFind.html#GST-TYPE-FIND-MAXIMUM:CAPS"><code class="literal">GST_TYPE_FIND_MAXIMUM</code></a>,
typefinding is stopped immediately and the found caps will be returned
right away. Otherwise, all available typefind functions will the tried,
and the caps with the highest probability will be returned, or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if
the content of <em class="parameter"><code>data</code></em>
 could not be identified.</p>
<p>When <em class="parameter"><code>extension</code></em>
 is not <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a>, this function will first try the typefind
functions for the given extension, which might speed up the typefinding
in many cases.</p>
<p>Free-function: gst_caps_unref</p>
<div class="refsect3">
<a name="gst-type-find-helper-for-data-with-extension.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>obj</p></td>
<td class="parameter_description"><p>object doing the typefinding, or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> (used for logging). </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="NULL is OK, both for passing and for returning."><span class="acronym">allow-none</span></acronym>]</span></td>
</tr>
<tr>
<td class="parameter_name"><p>data</p></td>
<td class="parameter_description"><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>a pointer with data to typefind. </p></li></ul></div></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Don't free data after the code is done."><span class="acronym">transfer none</span></acronym>][<acronym title="Parameter points to an array of items."><span class="acronym">array</span></acronym> length=size]</span></td>
</tr>
<tr>
<td class="parameter_name"><p>size</p></td>
<td class="parameter_description"><p>the size of <em class="parameter"><code>data</code></em>
</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>extension</p></td>
<td class="parameter_description"><p>extension of the media, or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a>. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="NULL is OK, both for passing and for returning."><span class="acronym">allow-none</span></acronym>]</span></td>
</tr>
<tr>
<td class="parameter_name"><p>prob</p></td>
<td class="parameter_description"><p>location to store the probability of the found
caps, or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a>. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Parameter for returning results. Default is transfer full."><span class="acronym">out</span></acronym>][<acronym title="NULL is OK, both for passing and for returning."><span class="acronym">allow-none</span></acronym>]</span></td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gst-type-find-helper-for-data-with-extension.returns"></a><h4>Returns</h4>
<p>the <a href="../html/GstCaps.html#GstCaps-struct"><span class="type">GstCaps</span></a> corresponding to the data,
or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if no type could be found. The caller should free the caps
returned with <a href="../html/GstCaps.html#gst-caps-unref"><code class="function">gst_caps_unref()</code></a>. </p>
<p><span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>][<acronym title="NULL may be passed as the value in, out, in-out; or as a return value."><span class="acronym">nullable</span></acronym>]</span></p>
</div>
<p class="since">Since: 1.16</p>
</div>
<hr>
<div class="refsect2">
<a name="GstTypeFindHelperGetRangeFunction"></a><h3>GstTypeFindHelperGetRangeFunction ()</h3>
<pre class="programlisting"><a href="../html/GstPad.html#GstFlowReturn"><span class="returnvalue">GstFlowReturn</span></a>
<span class="c_punctuation">(</span>*GstTypeFindHelperGetRangeFunction<span class="c_punctuation">)</span> (<em class="parameter"><code><a href="../html/GstObject.html#GstObject-struct"><span class="type">GstObject</span></a> *obj</code></em>,
                                      <em class="parameter"><code><a href="../html/GstObject.html#GstObject-struct"><span class="type">GstObject</span></a> *parent</code></em>,
                                      <em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guint64"><span class="type">guint64</span></a> offset</code></em>,
                                      <em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guint"><span class="type">guint</span></a> length</code></em>,
                                      <em class="parameter"><code><a href="../html/GstBuffer.html#GstBuffer-struct"><span class="type">GstBuffer</span></a> **buffer</code></em>);</pre>
<p>This function will be called by <a class="link" href="gstreamer-libs-GstTypeFindHelper.html#gst-type-find-helper-get-range" title="gst_type_find_helper_get_range ()"><code class="function">gst_type_find_helper_get_range()</code></a> when
typefinding functions request to peek at the data of a stream at certain
offsets. If this function returns GST_FLOW_OK, the result buffer will be
stored in <em class="parameter"><code>buffer</code></em>
. The  contents of <em class="parameter"><code>buffer</code></em>
 is invalid for any other
return value.</p>
<p>This function is supposed to behave exactly like a <a href="../html/GstPad.html#GstPadGetRangeFunction"><span class="type">GstPadGetRangeFunction</span></a>.</p>
<div class="refsect3">
<a name="GstTypeFindHelperGetRangeFunction.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>obj</p></td>
<td class="parameter_description"><p>a <a href="../html/GstObject.html#GstObject-struct"><span class="type">GstObject</span></a> that will handle the getrange request</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>parent</p></td>
<td class="parameter_description"><p>the parent of <em class="parameter"><code>obj</code></em>
or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a>. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="NULL is OK, both for passing and for returning."><span class="acronym">allow-none</span></acronym>]</span></td>
</tr>
<tr>
<td class="parameter_name"><p>offset</p></td>
<td class="parameter_description"><p>the offset of the range</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>length</p></td>
<td class="parameter_description"><p>the length of the range</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>buffer</p></td>
<td class="parameter_description"><p>a memory location to hold the result buffer. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Parameter for returning results. Default is transfer full."><span class="acronym">out</span></acronym>]</span></td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect3">
<a name="GstTypeFindHelperGetRangeFunction.returns"></a><h4>Returns</h4>
<p> GST_FLOW_OK for success</p>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-type-find-helper-get-range"></a><h3>gst_type_find_helper_get_range ()</h3>
<pre class="programlisting"><a href="../html/GstCaps.html#GstCaps-struct"><span class="returnvalue">GstCaps</span></a> *
gst_type_find_helper_get_range (<em class="parameter"><code><a href="../html/GstObject.html#GstObject-struct"><span class="type">GstObject</span></a> *obj</code></em>,
                                <em class="parameter"><code><a href="../html/GstObject.html#GstObject-struct"><span class="type">GstObject</span></a> *parent</code></em>,
                                <em class="parameter"><code><a class="link" href="gstreamer-libs-GstTypeFindHelper.html#GstTypeFindHelperGetRangeFunction" title="GstTypeFindHelperGetRangeFunction ()"><span class="type">GstTypeFindHelperGetRangeFunction</span></a> func</code></em>,
                                <em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guint64"><span class="type">guint64</span></a> size</code></em>,
                                <em class="parameter"><code>const <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gchar"><span class="type">gchar</span></a> *extension</code></em>,
                                <em class="parameter"><code><a href="../html/gstreamer-GstTypeFind.html#GstTypeFindProbability"><span class="type">GstTypeFindProbability</span></a> *prob</code></em>);</pre>
<p>Utility function to do pull-based typefinding. Unlike <a class="link" href="gstreamer-libs-GstTypeFindHelper.html#gst-type-find-helper" title="gst_type_find_helper ()"><code class="function">gst_type_find_helper()</code></a>
however, this function will use the specified function <em class="parameter"><code>func</code></em>
 to obtain the
data needed by the typefind functions, rather than operating on a given
source pad. This is useful mostly for elements like tag demuxers which
strip off data at the beginning and/or end of a file and want to typefind
the stripped data stream before adding their own source pad (the specified
callback can then call the upstream peer pad with offsets adjusted for the
tag size, for example).</p>
<p>When <em class="parameter"><code>extension</code></em>
 is not <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a>, this function will first try the typefind
functions for the given extension, which might speed up the typefinding
in many cases.</p>
<p>Free-function: gst_caps_unref</p>
<div class="refsect3">
<a name="gst-type-find-helper-get-range.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>obj</p></td>
<td class="parameter_description"><p>A <a href="../html/GstObject.html#GstObject-struct"><span class="type">GstObject</span></a> that will be passed as first argument to <em class="parameter"><code>func</code></em>
</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>parent</p></td>
<td class="parameter_description"><p>the parent of <em class="parameter"><code>obj</code></em>
or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a>. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="NULL is OK, both for passing and for returning."><span class="acronym">allow-none</span></acronym>]</span></td>
</tr>
<tr>
<td class="parameter_name"><p>func</p></td>
<td class="parameter_description"><p>A generic <a class="link" href="gstreamer-libs-GstTypeFindHelper.html#GstTypeFindHelperGetRangeFunction" title="GstTypeFindHelperGetRangeFunction ()"><span class="type">GstTypeFindHelperGetRangeFunction</span></a> that will
be used to access data at random offsets when doing the typefinding. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="The callback is valid only during the call to the method."><span class="acronym">scope call</span></acronym>]</span></td>
</tr>
<tr>
<td class="parameter_name"><p>size</p></td>
<td class="parameter_description"><p>The length in bytes</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>extension</p></td>
<td class="parameter_description"><p>extension of the media, or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a>. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="NULL is OK, both for passing and for returning."><span class="acronym">allow-none</span></acronym>]</span></td>
</tr>
<tr>
<td class="parameter_name"><p>prob</p></td>
<td class="parameter_description"><p>location to store the probability of the found
caps, or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a>. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Parameter for returning results. Default is transfer full."><span class="acronym">out</span></acronym>][<acronym title="NULL is OK, both for passing and for returning."><span class="acronym">allow-none</span></acronym>]</span></td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gst-type-find-helper-get-range.returns"></a><h4>Returns</h4>
<p>the <a href="../html/GstCaps.html#GstCaps-struct"><span class="type">GstCaps</span></a> corresponding to the data
stream.  Returns <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if no <a href="../html/GstCaps.html#GstCaps-struct"><span class="type">GstCaps</span></a> matches the data stream. </p>
<p><span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>][<acronym title="NULL may be passed as the value in, out, in-out; or as a return value."><span class="acronym">nullable</span></acronym>]</span></p>
</div>
</div>
</div>
<div class="refsect1">
<a name="gstreamer-libs-GstTypeFindHelper.other_details"></a><h2>Types and Values</h2>
</div>
</div>
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